Radio receiving system



mec., E5 11923.

L: DE FRET Filed July 2,

RADIO RECEIVING SYSTEM MAMA o Patented Bec. l, llfa a aan lr LEE DE FQREST, F NTEVV YGRK, N. Y.

RARE@ RECEIVING SYSTEM.

Application filed July 2,

To, all whom, if may concern.'

Be it known that l, LEE nn Fenner, a cit izen ot the United States, residing at New York, in the county and State or' New York, vhave made a certain new and useful lnvention in Radio Receiving Systems, ot which the following is a speeitication.

This invention. relates to radio receiving systems.

The object of the. invention is to provide a radio receiving system which is simple and cilicient in operation.

A further objecty of the invention is to provide a radio system wherein the signals are received in the telephone receivers as clear notes.

further object oi the invention is to cblain in. telephone receivers a response to undampcd Wave train signals of constant amplitude received through the anlenme system at the receiving station, the said response being in the form of a musical note. Without the intermediary of a tikker, tone Wheel, or mechanical` interrupter or' any kind, and7 further, Without using the principle of heterodyne or beat note reception Which requires a local source o't oscillations present invention to obtain at a receiving" station the benefits incident to the reception of signals by the heterodyne or beat note phenomena or by the use of mechanical iuterruptcrs or the like, Without the disadvantages incident thereto, namely, 4in the first instance, ot' the requiren'ient. of a local source of oscillation, and. in the second-instance.7 of mechanical means and apparatus incident thereto. ln accordance'ivith my invention, I cause the incoming undamped 1920. Serial no. 393,609.

wave train of the signal to produce electrical operations Which automatically act to periodically interrupt or, at least., greatly reduce the amplitude of the said undamped Wave train; and at a rate or periodicity of interruption or fluctuation of amplitude which can be varied Within suitable limits by the receiving operator. @ne arrangement of circuits for producing the desired operation above outlined is shown in Figure l. wherein l7 2, 3, and l illustrate the usual typical receiving' antennzc system comprising the aerial, primary inductauce. series variable condenser and earth connection respectively. The secondary system of the receiver circuit comp ises, in the form shown, the coil 5 of the radio frequency transformer, preferably loosely coupled to the primary of the transformer 2, and the loading coil 6 and variable condenser T in series therewith. This tuned secondary system is connected to the detector Which, as illustrated, is an audion or three electrode udevice. one terminal of the circuit being connected to the lilament electrode of the audion and the other terminal of the plate electrode of the audion through the primary Winding 8 ot an audio Jfrequency transformer, preferably with an iron core, as illustrated. Across this Winding- 53 is connected a condenser lO of a capacity designed to bypass the radio frequency currents 'lrom the receivineV secondary circuit but not suiliciently large to needlessly shunt the audio trequcncy currents in the coil S. Connected as shown, it will be seen that the audion 2i is merely acting as a rectifier ot the received high frequency currents` which rectication action for two electrode devices has long been known as the Edison effect. The third electrode or grid ofthe audion comes into operation only in connection with the audio frequency currents delivered thereto from the audio frequency amplifying audion 18 in a manner and Jfor a purpose which will be more Jfully hereinafter set Jforth.

ln the operation of the circuits and devices so tar described, the reception of a signal comprised of one long undamped Wave train Would ordinarily set up inthe circuit-connecting the filament and plate electrode of the audion 2l a direct current. On account of the/presence in the tuned secondary circuit of the loading coil 6 a relatively long periodvof current rise exists be- W shari' or 'Cause tween .the time of he `nning the signal and the time when the direct current in the sec` ondary circuit attains a constant maximum amplitude. The forni of circuit curve Which would `be thus obtained in the secondary circuit is shown in curve 1 of Fig. 3, namely, a relatively gradual rise to horizontal line ot' maximum amplitude, indicated -by the dotted lie 50. rlhis period of rise can be made long accordingto the degree of Stillness of the secondary circuit and its looseness of coupling to the primary circuit. This change of current from zero to mairimum in the primary Winding of the audio frequency transformer 8 induces a momentary pulse of current in the secondary Wind-- ing. 9 thereoas illustrated in curve 2 olf w. 3. This single pulse ol'current in the @ai 9` is deiiverai to the ged-filament of the audion amplifier 18, thereby reducing" a corresponding but greatly amplified current pulse having essentially the same Wave form in the plate .lament or output circuit of the audion amplifier 18. Energy for this ani-- plified pulse is supplied from the usual B orplate battery 27 connected between the plate and filament of audion 18. This amplified impulse passing through the primary Winding 24 of an audio frequency transformer induces in the secondary Winding 25 thereof a double pulse indicated in curve 3 of Fig. 3.' Thesecondary winding 25 of the audio frequency vtransformer is preferably, and as shown, sofconnected to the grid and filament of audion21 with the first half of the current pulse in 25 which places a negative charge on the grid 23 as shown at cui-ve 3 of Fig. 3.' The negative half of this alternating current impulse will build up on the grid 23 of audion 21 a negative charge of relatively high potential, which will act to more or lesscompletely interrupt the passage between tlie plate and filament ofthe audion 2l of the rectified wave train, thereby causing the current curve illustrated as curve 1 of Fig. 3, to fall from 51 to 52, 52 being on or near the zero axis. This current change will in turn induce a positive current pulse in coil 9 and a similar amplified pulse in coil 24 and thus a positive grid elect-rode 23 ot' audion 21 which, taken in conjunction with the lust preceding negative voltage charge on the grid electrode 253, will again permit the rectified current in the circuit 5, 6, S. to rie-establish iteeli' as shown in curve 1 of Figf-l. through 53 to 54. This increase ot current through coil 8 will again pulse in mil f) and thus another double pulse on Agrid 23. from which it will be seen that a recurring` cycle of rectified cur- 'V rent increasing to maximum and automatically cut off tozei'o orlnearly zero will result 'so long asthe incoming Wave train continues. A telephone receiver 26 in series with the plate lament circuit and audion voltage charge upon the.

recense amplilier 18 Will, therefore, produce a. musical note so longl as the Wave train is continued. The pitch of this note vvill depend upon the electrical constants inthe audio frequency circuit and also upon the characteristics of the-two audion bulbs, the voltage impressed on the grid 1G of audion 18, Afrom C battery 14 connected in the biasing or the usual. manner. Thus the pitch ci' the 'note can be lowered by connecting a 'Fairly nal cut-od or minimum current fion' at .52

of curve 1, Fig. 3. -It will also `be that there is also a. time lag between this point of minimum current and the beginning of the next successive increase olf curapparent rent; i. e., between the point 52 and 53. rllie -1 duration' of these time lags, as Well as the shapes of the current curves at the beginning and end of impulse, and therefore the exact timbre or sound quality of the note heard in telephone receiver 26, depends upon the electrical constants of the circuit` the amount of iron in the cores ci the transformers 8, 9, and 24, 25, etc.

l'lllhe method herein illustrated of obtaining from a continuous received Wave train a musical note in the telephone receiver is usually independent of the radio tuning oi' transmitter and receiver. This fact is a decidedL advantage because in lieteiodyne receiving it-fiequently occurs Athatby slight changes in thevvvave 'frequency'eithei at the transmitter or receiving stations, due to inadventent approachof the operators body to parts of the circuits or the switching of the antennae systems in the Wind, etc., considerable and annoying changes in the note of the signal are produced. As above stated, and as will be apparent, the system oi my invention is free from sucliobjection. Any degree of sensitiveness of reception can easily be obtained by using one or more steps of radio or audio frequency amplification loetWeen the antennae system and the telephone receiver. I

If desired, and as shown, choke coil 30 may be inserted in the input or grid filament circuit oi' the amplifier 18. The system illustrated in Fig. 2 is lsubstantially the same as that shown iniFig. 1, with the addition or' a third Winding it) about the iron core of the transformer 242 and 25. In series with the Winding 40 is connected a source of current, such as a battery 3l, and 'rheostat 32 (Wliich,"hoWever, may be omitted).

a high frequency. i

vThe object of this addivlll 'eficaces tional circuit is to saturate the iron core of the transformer 2d', 25, in such a direction that the electro-motive torce induced in the secondary is uni-directional only, and so connected to the grid filament electrodes out' the audion 2l, asto make the grid thereof negative only when a current, pulse occurs in the primary Winding The circuits may be supplied with the usual adjustments now Well understood in the artV and With the usual variance in circuit details now understood to be optional with any particular 'circuit arrangement.

Many modiiications and changes, theretore, may readily occur to those skilled in the art, Without departing from the spirit and scope of my invention.

Having set forth, however, the objects and nature of my invention and having shown and described a circuit arrangement illustrating the method contemplated for the reception of signals in accordance 'there` with, what claim as new and useful, and of my oW-n invention, and desire to secure by Letters Patent is l. rlhe method of receiving radio signals which comprises utilizing the received high frequency current toiintcrrupt itselt" to Cil thereby produce current impulses ot' rela tively lower frequency.

2. The method of receiving radio signals 'which comprises utilizing the received high frequency current to interrupt itselt' to thereby produce current impulses ot' audio frequency.

3. The method ot' producing an audible signal in-a radio receiving system which comprisesutilizing the received signal current to automatically interrupt its-ell.

4. The method ot' producing an audible musical note signal in a radio receiving svstem, jvhicli comprises utilizing` the received signal current to aut-omaticallj.Y interrupt itself.

5. rflic method olE producing; an audible signal in a radio receiving system for undamped wave train signals which conupiics utilizing the received signal current tor automatically interrupting` the wave train.

6. The method ot producing anzuuliblc musical note signal in a radio recciviincr tem, for undaiupcd wave train signals which con'iprises utilizingl the received signal currentforautomatically interrupting;- the wave train.. Y

T. ln a receiving system, and `in combination with means 'for receiving an undamped wave train ofthe transmitted sin-- nal. of means automatically operated by the received Wave train tor interrupting the Wave train to reduce the amplitude ol the received undamped wave train.

8. In n receiving system. and in combination with means for receiving an undainped Wave train ofthe transmitted signal, ot'

means automatically operated by the received Wave train for periodically inter` rupting the received Wave train,

9. ln a receiving system, and in combi nation with means tor receiving an undamped Wave train ot' the transmitted signal, of means automatically operated by the received Wave train :for,interrupting the wave train to periodicallvreduce the amplitude of the received undamped wave train.

l0. In a receiving system, and in combination with means for receiving an undarnned Wave train the transmitted. nal, of means automatically operated by the received wave train for periodically interrupting the received Wave train. and 'means for varying; the periodicity ot interruption of the Wave train.

ll. vln a receiving system. and in combination with means tor receiving an undaniped Wave train of the transmitted signal, ot electrically operating means operated by the received wave train 'for periodically interruptingl the received wave train. and means tor varying the periodicity ot' interruption of the Wave train.-

.Tn a receiving system, and in combination 'with means for receiving an undamped wave train oit' the transmitted signal, ot' means automatically operated by the received wave train for interrupting?T the wave train to periodically reduce the amplitudc ot the received uncamped ware train. and means tor varying' the periodicity ot tluctuation ot' amplitude ot the Wave train.

lll. ln a receivingr system, and in combination with means for receiving an undarnped wave train ot' the transniitted signal, of electrically operating' means operated by the received Wave train for interrup'tinrcr thc Wave train to periodically reduce the amplitude of the received undamped wave train. and for varying the periodicity ot' liuctuation of amplitude oi the Wave train.

M. ln a radio frequency receiving system, and in comliinatum with means for receiving an` undampcd wave train of the transmitted signal` means for rectitying the received radio frequency energy, a secondary circuit. rnc-ans controlled by the rectilied radio frequency energy l'or inducing a cur-- rent pulse in said secorulary circuit, and

means controlled by lcurrent pulse in said.

secondary circuit for rendering said recti- Vtying means inoperative.

l5. ln a radio frequency receivingr system, and in combinatiin'i with t'or receiving' an undamped wave train ot the transmitted signahmeans 't'or rcctit'ying the received radio frequency energy, a secondary circuit, means controlled by the rectified radio 'frequency energy for inducing;A acurrent pulse in said secondary circuit, means controlled by the current pulse in said secciliating circuit and controlhul @tit ondary circuit for rendering said rectifying means inoperative, and a signal indicating device controlled by 16. In a radio ltrequency receiving system7 and in combination with means for receiving an undamped were train of the transmitted signal, means .t'or rectifying the received radio frequency energy, a secondary circuit, means controlled by the rectified radio frequency energy for inducing' a curs rent pulse in said secondary circuit, means for amplifying the current pulse induced in said secondary circuiti, and means controlled by the amplified ycurrent, pulse in said serL ondary circuit tor rendering said rectiifvinf; means inoperative.

1.7. In a radio frequency'receiving system, and in combination with means for receivingan undamped wave train ot the trans` mitted signal, means for i'ectitying the received radio frequency energy. a secondary circuit, means controlled by the reetiliml radio frequency energy tor inducing a current pulse in said secondary circuit. means for amplifying' the current pulse induced in said secondary circuit` troiled by the amplified current pulse in said secondary circuit for rendering said rectifying means inoperative, and a signal indicating device controlled by said secondary circuit.

i8. In a, radio receiving.: system, and in combination with. 4an antenna system, nl an oscillating circuit associated tnereu'itl.. including two terminals ol' a tlicrniiouic tube, a. seconda-ry circuit :"ssociatml with :raid oslluircby. ine-ans for inducing audirI tri-fluency pulsations in said secondary circuit by the energy supplied said oscillatingl circuit', and means for supplying' s id audio trequcnor luilsations to tivo terminals of said thei` minnie tube.

19. In a, radio receivingv sys-'trim combination with an antenna t: tu. ot' an cva rated vessel haring asso'iatcd thereY Wi .i a hot and two cold electrodes. an oscillzitinna circuit including' tbc hot am; one cold electrode ot said vessel. a secondary circuit associated with said oscillating cirW Cuit and eontrclled thereby. means for iad'ucinfr audio t'rcquci'ic-r l'uilsations in said seIondary circuit by 1hr energy' supplied said oscillating circuit. and means vl'or supplying' said audio frequency pulsations` to the other ot' 'the cold elcctroifles o'l said vessel.

20. in a, radio receiving' system, and in coniiiination with an antenna s -rtcn1. oi' an evacuated if, :'l havin;Y associated therewith filament. ,l

and in and nlate chictrodes said secondary circuit.-

and means con of an oscillating circuit connected to the vfilament and plate'electrot'les, a secondary an oscillating circuit connected to the `fila-ji ment and plate electria'les` a secondary circuit associated with said oscillating,r circuitand controlled thereby. said secondary circuit conip'rising the input circuit of an audion amplifier system. means 'for inducing audio frequency pulsations in said secondary circuit by the energy supplied said orcillating' circuit, the output circuitot' said audion amplifier with tbegrird electrode of said vessel.

22. ln a radio receivingv system.l and in combination with an antenna system. of an eracua'ted vessel having',r associated therewith tilanient, .grid and plate electrodes. oli' an oscillatini,r circuit connected tothe lilainent and plate electrodes, a secondary cirfuit associated with said oscillating' circuit and controlled thereby, said secondary circuit. comprising the input circuit ot an audion amplifier system. means for indueinnu audio frequency' pulsations in said secondary circuit by the energy supplied said oscillating circuit` the output circuit ot said audion amplifier system being' associated with the grid electrode ot' said vessel, and a signal indicating' devii'c included in the output circuit ot' said audion amplifier system.

:28. Means for producing' a. musical note signal 'at "af radio receiving station from a rereiyed continuous Wave train, comprisingr a rectifier For the received energy, and means operated by the received energy for rendering' said rectifier inoperative.

524i. Means 'tor producing a musical note Signal at a radio receiving station from a received contini-mus waive train, comprisinc; a. rectiticr 't'or the received energy, land means operated by the reeeivedenergy for .renderingsaid rectifier inoperative, and a signal responsivedevice included ina, circuit, associated with said rectifier.

In testimony whereof i have hereunto setrni' hand on this 26th day of June A. D.,

system being' associated' 

